The invention relates in general to elevator call registering and indicating devices and, in particular, to such devices for the immediate assignment of destination calls.
One known type of elevator call registering and indicating device has a keyboard for the input of calls for desired floors of destination, call memories and an indicating element which signals the desired floor of destination. A first control circuit, connected with the keyboard and the indicating element, activates the indicating element at the input of a call.
U.S. Pat. No. 3,493,922 shows a call registering and indicating device arranged in an elevator car which has a ten key keyboard for the input of car calls and an indicating panel for the indication of the selected floor. In order for the entered call to be stored and transferred to the elevator control, an additional registering key has to be actuated within a predetermined time. If the registering key is not actuated, it will light up after expiration of the predetermined time. The entered call is automatically cancelled after a further predetermined time if no action is taken in response to this signal. A further key permits a call to be cancelled, if it was, for example, entered incorrectly or erroneously. As can be seen from the preceding, the call input or entering requires increased attention of the passenger. Also, incorrectly entered calls or carelessness result in an increased loss of time for each entered call, so that in the case of several simultaneously entering passengers, unpleasant situations can arise due to delays.
A group control for elevators, shown in the European Patent Application No. 0,246,395, has call registering devices which include a ten key keyboard. However, the call registering devices are located at the floors and no call buttons are provided in the elevator cars. Calls for desired floors of destination are entered and a call characterizing the input floor is stored in the floor call memories and the calls characterizing the floors of destination are stored in the car call memories of the elevators. In order to simplify and accelerate the call entering process, the call registering device includes, in place of the registering push button used in the prior art devices, a time limiting circuit. The limiting circuit is activated on input of a first number and requires that the second number of a call has to be entered within a predetermined time, wherein the entered call is automatically registered after expiration of this time. If the second number is not entered in the time limitation however, it is possible to experience incorrect call entries.
The group control described above has a computer in the form of a microprocessor and a comparison device for each elevator. The computer, immediately after the registration of a call and from data specific to the elevator, calculates a sum corresponding to the average waiting time of the passengers, also called operating costs. During a comparison of the operating costs of all elevators following immediately thereafter, the elevator with the smallest operating costs is determined, to which elevator the respective call is then assigned. Since at the input of the call at a floor, a car call characterizing the desired floor of destination is also being stored, the latter can also be considered in the calculation of the operating costs, so that the car established in the comparison is not only the most advantageous for the servicing of the input floor, but also for the floor of destination.
In group controls in which the floor and car calls are entered in a customary manner by means of call buttons arranged on the floors and respectively in the car, a passenger has to select twice in order to arrive at his/her destination. The control device is therefore informed relatively late of the desired destination of travel, which destination therefore cannot be considered for the assignment of the respective floor call. The car determined in the course of the assignment process is therefore the most advantageous for the respective floor call, but generally not for the destination unknown at the time of calculation. To obtain better results, as shown for example in European Pat. No. 0,032,213, the calculation and assignment of a floor call is postponed to a time at which the transfer to the drive control has to take place for the purpose of initiation of the stop at the respective floor. Under this method of operation, the assigned car can be made known to the passengers waiting at a floor only shortly prior to arrival, for example, through illumination of a direction indicator arranged above the respective elevator door and by an acoustical signal. In larger installations with several elevators, this operation could give rise to difficulties for the passengers, as there remains relatively little time to recognize the indication and to move in time to the indicated elevator.